Understanding your device’s limitations will save you hours of frustration. The VIVO S1 is a great phone, but it is not built for developer-friendly Fastboot access.
Instead of the traditional black screen with "FASTBOOT" in large letters, many VIVO S1 units will boot into a "Factory Mode" or "eMMC Test Mode" after this key combination. This is because VIVO restricts direct Fastboot access. From here, you can sometimes navigate to a Fastboot option, but it is rare. How to Open Fastboot Mode on VIVO S1
The primary way to access Fastboot Mode is by using a specific physical button sequence while the device is powered off. This is because VIVO restricts direct Fastboot access
: Once in Fastboot Mode, use the Volume Up/Down buttons to highlight options and the Power button to confirm your selection. Alternative Method: Using ADB Commands (PC Required) : Once in Fastboot Mode, use the Volume